Many wastewater steams include substantial amounts of mixed salts. Various countries passed and continue to pass various regulations that propagate strict standards for wastewater disposal. Streams with substantial contaminants, therefore, cannot be traditionally disposed in these countries. There is a need for a cost effective treatment to remove contaminants from these wastewater streams, such as through salt production.
One example of a wastewater stream that contains substantial contaminants and cannot be traditionally disposed in some areas of the world is the wastewater stream produced in coal to liquid or coal to chemical processes. Coal to liquid processes allow coal to be processed into useful materials such as liquid fuel. These processes are especially useful in regions that have an abundance of coal but do not have enough oil to meet demands. Although coal to liquid processes are overall attractive, they yield wastewater effluents that are often problematic to process. Treatment of these wastewater streams through typical treatment methods results in production of a mixed salt comprised of sodium sulfate and sodium chloride along with various other contaminants. Under various regulatory requirements in various countries, these mixed salts cannot be disposed of in a landfill.